NMEA 0183 overview

The NMEA interface allows the camera to communicate with radar, GPS, or other third-party devices using the National Marine Electronics Association (NMEA) 0183 protocol. NMEA 0183 (or NMEA for short) is a combined electrical and data specification for communication between marine electronic devices.

For information on how to connect NMEA 0183 devices to the camera, refer to: NMEA 0183 connection

For additional information regarding the NMEA 0183 protocol, refer to: https://www.nmea.org

When it receives valid NMEA 0183 sentences from connected NMEA 0183 devices, the camera can automatically point itself towards vessels and other objects in its field of view, and track their movement. The camera can receive 3 types of NMEA messages:

  • Radar Cursor Tracking, which is implemented using the NMEA Radar System Data (RSD) sentence.

  • Slew to Waypoint, which uses the NMEA Bearing and Distance to Waypoint, Great Circle (BWC) sentence.

  • Radar Tracking, which uses the NMEA Tracked Target Message (TTM) sentence.

Note

All 3 (or any combination) of these NMEA messages can be enabled via the camera’s NMEA interface. When more than one type is enabled, the system processes RSD first, then BWC, and finally TTM. For example, if the unit is listening to BWC or TTM messages and looking at a particular target and it receives an RSD message, it waits until the end of the dwell time and then moves on to the RSD message, ignoring all other input.

Note

Even though you can only enable up to 3 types of messages via the camera’s NMEA interface, the camera uses additional messages to perform the calculations needed to respond to these 3 message types. If your camera is not responding as expected, verify that the NMEA device sending messages is sending the following additional message types to your system:

  • HDT (Heading — True)

  • GGA (Global Positioning System Fix Data)

  • VHW (Water Speed and Heading)

  • OSD (Own Ship Data)

  • TLL (Target Latitude and Longitude)

Important

In order for the NMEA features to work correctly, the camera’s altitude above the waterline must be specified using the camera’s Web interface. Enter the altitude by accessing the Web interface and selecting the Georeference tab.